The present invention relates to a valve for closing, throttling or regulating, and in particular to a regulating valve in an automatic control system, consisting of a housing with a cylindrical closing-adjusting cone guided therein.
A great variety of types of closing mechanisms such as cocks or valves have been known. Cocks are constructed usually for small diameters and low pressures, while valves are constructed for larger diameters up to the highest pressures. One of the first conditions for a valve which is used for closing or throttling is the necessity of maintaining the valve gas tight in continuous operation. At the same time valves which are used for throttling are subject to particularly hard wear and tear. An additional condition for closing or throttling valves is their ease in opening and closing. This condition is also necessary for regulating valves which must be tight in the case of closing.
In the case of regulating valves, parabolic or bell-shaped cones are used as adjusting members which are flown against essentially on the front side. This type of regulation is conditioned on the fact that the regulating members must always be pushed against the flow of the material onto their bushing seat in order to close the armature. Thus, high adjusting forces result in direct dependence of the operating pressure existing at any time, which then acts as a differential pressure on the cone. This fact causes the occurrence of a hysteresis in the operating behavior which has very unpleasant consequences for the entire regulating valve, whereby the precision for regulation is influenced decisively.
Swiss Pat. No. 11,217 discloses a closing valve provided with a simple regulating cock having a cylindrical closing cone guided therein. In order to move the closing cone, however, large forces are necessary in order to overcome the frictional forces between the closing cone and the housing, so that this regulating cock is unsuitable particularly for regulation. U.S. Pat. No. 1,805,106 likewise discloses a throttle valve with a cylindrical closing cone for the movement of which likewise large frictional forces must be overcome. This throttle valve too is not suited for use in a regulating circuit of an automatic control system. Furthermore, from closure engineering, a large number of simple cocks or closing organs have been known in order to interrupt the flow of substances, which are more or less suitable for a tight closure of conducting systems, U.S. Pat. No. 3,526,249 contains, for example, a disclosure of a closing cock with a ball chick, in which an additional slide has been disposed. In terminal position the slide has a seat in the ball chick, whereby regulation of the flow of the stream of substance is not possible.
Furthermore, valves have been known which have control edges which are shaped in a certain way in order to impart a square or logarithmic characteristic line to the valve. British Pat. No 111,631 discloses a throttle valve with a flat slide disposed transversely to the flow of substance, whereby the control edge of the flat slide valve is developed in the shape of an arc or triangularly.
The present invention is based on the task of creating a valve of the initially mentioned type which, in order to move the closing-adjusting cone, the latter need overcome only very slight frictional forces between the cone and the housing; furthermore, the valve is to show practically no hysteresis.
The solution of this task consists in the fact that according to the present invention the closing-adjusting cone is a hollow cylinder which, while recessing a part of the cylinder jacket, is developed with an opening throughout from the upper to the lower cylinder cover surface as a partial shell.
The valve with its closing-adjusting cone developed according to the present invention has the important advantage that it practically has no hysteresis. The necessary forces for moving the closing-adjusting cone are reduced to a minimum, since complete pressure compensation develops within the closing or adjusting cone. The operating pressure is noticeable only by way of frictional forces between the partial shell and its guide within the housing. These frictional forces, however, are further reduced through the fact that the hollow cylinder, on the basis of its development as a partial shell and with thermal load, may adapt itself permanently to the expansion of its guide track, so that the operational behavior of the closing-adjusting cone, even in the case of very high temperatures, is without any problem. No jamming can occur on the basis of thermal expansion of the closing-adjusting cone.
Furthermore, the hollow cylinder in its upper part may have an annular groove. A traverse is firmly disposed in the annular groove on which a guide bar is disposed in the middle for the movement of the hollow cylinder. On the basis of the pressure compensation within the shell-shaped closing-adjusting cone, no transverse forces act on the guide bar which likewise contributes to the elimination of hysteresis. At the same time the traverse may be attached power coupled in the annular groove of the hollow cylinder, and the guide bar may likewise be connected firmly with the traverse so that the closing-adjusting cone is also rotatable around its longitudinal axis.
Furthermore, in an advantageous development of the present invention, the cylinder jacket may have a recess opposite the opening, wich extends up from the lower cylinder cover surface. This recess may be a bent rectangle or triangle in accordance with the cylinder jacket. Beyond that the lower edge of the jacket surface of the hollow cylinder may describe a curved line which is symmetrical to the middle, longitudinal axis lying in the partial shell, where by the edge travels around a recess inside the cylinder jacket surface which ends in a horizontal slit. Thus, all characteristic lines may be traveled, be they linear, square or logarithmic.
As a result of the fact that the closing-adjusting cone is developed as a partial shell, very slight production tolerances may be maintained between the housing and the closing-adjusting cone. As a result of this the valve according to the present invention is distinguished additionally by a very high degree of tightness. Furthermore, the shell-shaped closing-adjusting cone will permit the insertion of working materials which have a degree of hardness of 9, for example, oxide ceramics, glass ceramics, hard metals, etc. At the same time, both the housing as well as the closing-adjusting cone may be produced from one of these working materials. These working materials may be used because the closing-adjusting cone according to the present invention need not be forced down onto a valve seat in the housing for a complete closure contrary to parabolic or bell type cones or others, but the complete closure of the valve is achieved by a covering up of the continuous bore of the housing. As a result of that, furthermore, an easier production of the housing of the valve according to the present invention exists. As an additional working material, hard metal is also possibly suitable in this case.
The valve according to the present invention is suited for closure, throttling or regulation, where the highest degree of tightness and functional efficiency is required. The valve according to the present invention is suited especially for use as a regulating valve in an automatic control system, whereby only small adjusting forces are needed -- as compared to the high and maximum pressures which may be controlled with the valve according to the present invention, which adjusting forces amount to only a fraction of those adjusting forces which are required in the case of regulating valves for the regulation of comparable pressures.